Housed in the back of the Artisan Studios in Del Paso Heights, the pastor walked out of his sanctuary to investigate.

Vertical banners and a parking sandwich board sign indicate which building and which lot are used for services.

"They were parked right here in this corner, so obviously they could see the sign," Vaiz said.

The signage -- even more important because ICE, or Immigration and Customs Enforcement, has stated that even with the ramped up focus on the undocumented under the Trump administration, the agency's staying away from sensitive areas like churches.

"We don't arrest people on school grounds. We don't arrest people in churches," said ICE National Director Thomas Homan, during his March visit to Sacramento.

"You could see the vest saying police on the back and with a small badge saying ICE in the front. They told me 'We're investigating an individual in this area.'"

With about 60 percent of his congregation without legal standing to be in the U.S., that quick visit and departure produced concern.

When officers were spotted returning about 90 minutes into service, that concern elevated to panic, even though the officers left quickly.

"I couldn't believe that it was happening," said Vaiz.

By phone, ICE's Northern California Director, James Schwab, told FOX40 the sound of such an operation is "not typical," that a church is considered a "sensitive location" and that such a visit would be "extremely rare -- especially on a holiday."

Schwab also said it's possible that Vaiz only saw the last three letters of a spaced out "POLICE" label on the badge.

Still, the agency is researching if there was ICE activity in Del Paso Heights on Mother's Day.

Pastor Vaiz has no doubt.

The Mexican consulate has sent a letter to ICE on behalf of Vida Church.